1 /* Copyright (C) 2001-2022 Free Software Foundation, Inc.
2    This file is part of the GNU C Library.
3 
4    The GNU C Library is free software; you can redistribute it and/or
5    modify it under the terms of the GNU Lesser General Public
6    License as published by the Free Software Foundation; either
7    version 2.1 of the License, or (at your option) any later version.
8 
9    The GNU C Library is distributed in the hope that it will be useful,
10    but WITHOUT ANY WARRANTY; without even the implied warranty of
11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
12    Lesser General Public License for more details.
13 
14    You should have received a copy of the GNU Lesser General Public
15    License along with the GNU C Library; if not, see
16    <https://www.gnu.org/licenses/>.  */
17 
18 #include <dirent.h>
19 #include <stddef.h>
20 #include <hurd.h>
21 #include <hurd/fs.h>
22 #include <hurd/fd.h>
23 #include "dirstream.h"
24 
25 /* Read a directory entry from DIRP.  */
26 struct dirent64 *
__readdir64(DIR * dirp)27 __readdir64 (DIR *dirp)
28 {
29   struct dirent64 *dp;
30 
31   if (dirp == NULL)
32     {
33       errno = EINVAL;
34       return NULL;
35     }
36 
37   __libc_lock_lock (dirp->__lock);
38 
39   do
40     {
41       if (dirp->__ptr - dirp->__data >= dirp->__size)
42 	{
43 	  /* We've emptied out our buffer.  Refill it.  */
44 
45 	  char *data = dirp->__data;
46 	  int nentries;
47 	  error_t err;
48 
49 	  if (err = HURD_FD_PORT_USE (dirp->__fd,
50 				      __dir_readdir (port,
51 						     &data, &dirp->__size,
52 						     dirp->__entry_ptr,
53 						     -1, 0, &nentries)))
54 	    {
55 	      __hurd_fail (err);
56 	      dp = NULL;
57 	      break;
58 	    }
59 
60 	  /* DATA now corresponds to entry index DIRP->__entry_ptr.  */
61 	  dirp->__entry_data = dirp->__entry_ptr;
62 
63 	  if (data != dirp->__data)
64 	    {
65 	      /* The data was passed out of line, so our old buffer is no
66 		 longer useful.  Deallocate the old buffer and reset our
67 		 information for the new buffer.  */
68 	      __vm_deallocate (__mach_task_self (),
69 			       (vm_address_t) dirp->__data,
70 			       dirp->__allocation);
71 	      dirp->__data = data;
72 	      dirp->__allocation = round_page (dirp->__size);
73 	    }
74 
75 	  /* Reset the pointer into the buffer.  */
76 	  dirp->__ptr = dirp->__data;
77 
78 	  if (nentries == 0)
79 	    {
80 	      /* End of file.  */
81 	      dp = NULL;
82 	      break;
83 	    }
84 
85 	  /* We trust the filesystem to return correct data and so we
86 	     ignore NENTRIES.  */
87 	}
88 
89       dp = (struct dirent64 *) dirp->__ptr;
90       dirp->__ptr += dp->d_reclen;
91       ++dirp->__entry_ptr;
92 
93       /* Loop to ignore deleted files.  */
94     } while (dp->d_fileno == 0);
95 
96   __libc_lock_unlock (dirp->__lock);
97 
98   return dp;
99 }
100 
101 libc_hidden_def (__readdir64)
102 weak_alias (__readdir64, readdir64)
103